In a conventionally known electronic organ, electronic piano or other automatic performing apparatus, the accompaniment pattern is stored for every chord type, such as major, minor and seventh chords. In response to the depression of keys, the chord type is determined and the accompaniment pattern corresponding to that chord type is selected. Sound is generated according to the selected accompaniment pattern.
In an automatic performing apparatus, an automatic accompaniment function is provided, such that the accompaniment part of rhythm, bass and arpeggio data is automatically reproduced.
For the automatic accompaniment, rhythm, bass and arpeggio data for the same number of bars are stored in an automatic accompaniment memory. Specifically, as shown in FIG. 18, sound tone and generating timing for each accompaniment part are mixedly stored in one sequence track of rhythm R, bass B and arpeggio A.
The sequence track of the automatic accompaniment memory shown in FIG. 18 is accessible with only one pointer, because rhythm R, bass B and arpeggio A are stored together. However, the data for the least common multiple of looped bars among rhythm R, bass B and arpeggio A needs to be stored.
For example, if two bars of rhythm R, four bars of bass B and one bar of arpeggio A are required in a loop, an accompaniment part consisting of four bars needs to be stored. The data shown by the slashed lines in FIG. 18 are overlapped in the same loop. For example, the data A2, A3 and A4 have the content identical to that of data A1. The automatic accompaniment memory is thus inefficiently used.
Recently, as the quality of musical performance has been enhanced, the number of bars in a loop have increased. Wasted memory remains a problem.
To efficiently use the accompaniment memory, a track may be provided for each accompaniment part, such that the bars in a loop are stored and reproduced. If rhythm style is changed halfway through the accompaniment, however, the bar at which the new rhythm style is to be started in each accompaniment part cannot be identified.
The aforementioned problem is especially prevalent in the electronic organ, since if the rhythm style is changed, the accompaniment is continued from the bar of the new rhythm style corresponding to the bar which was played before the rhythm style had been changed.
Also, in conventionally known electronic organs, electronic pianos, or other automatic performing apparatus, the automatic accompaniment function is provided, such that the accompaniment part is performed based on the accompaniment pattern stored for each chord type.
The accompaniment patterns corresponding to each chord type are stored. In response to the depressing of keys, the particular chord type is determined. According to the accompaniment pattern corresponding to the determined chord type, sound is generated.
To conserve and efficiently use the memory of the automatic performing system, Japanese Laid-open Patent Application No. 63-193200 proposes the storing of the accompaniment pattern for each chord type group. The chord types are divided into major and minor mode groups.
In this method, the accompaniment patterns corresponding to each chord type group are stored. In response to the depression of keys, the particular chord type is detected, the chord type group containing the detected chord type is located, the accompaniment pattern corresponding to the located chord type group is selected, and sound is generated according to the accompaniment pattern.
The prior art, however, contains disadvantages. Usually, the accompaniment patterns are stored in different sequence tracks or areas. As aforementioned, when the accompaniment pattern for each chord type group is stored in response to the player's depressing of keys, a data reading pointer should jump to the accompaniment pattern corresponding to the desired chord type group. Alternatively, respective pointers for each chord type group should work coincidentally. The processing in the CPU is complicated, and unwanted delay in performance may arise.
Also, the accompaniment pattern for each chord type group is stored in a different sequence track, thus, even if the accompaniment patterns are partly the same, they have to be independently stored. Furthermore, every sequence track requires a bar marking, thereby increasing the volume of accompaniment pattern memory.